There are many types of electric boxes, most are made out of metal but some are made out of plastic. In some instances, some of those boxes are shallow. However, because of the way they are constructed, when comes time to install hem or run wires into them, there is the need to cut holes through the polyethylene vapor barrier, which has an impact on its properties. Also, the wires that come inside the box are often connected to the outlet or switch in a complicated manner and then pushed inside the box so that everything can be fitted inside the box.